iOS 中怎么设置label中的内容是靠最上面显示，，还是在中间显示

#import

typedef enum
{
    VerticalAlignmentTop = 0, // default
    VerticalAlignmentMiddle,
    VerticalAlignmentBottom,
} VerticalAlignment;

@interface myUILabel : UILabel
{
@private
    VerticalAlignment _verticalAlignment;
}
@property (nonatomic) VerticalAlignment verticalAlignment;

@end

#import "myUILabel.h"

@implementation myUILabel
@synthesize verticalAlignment = verticalAlignment_;
- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        self.verticalAlignment = VerticalAlignmentMiddle;
    }
    return self;
}

- (void)setVerticalAlignment:(VerticalAlignment)verticalAlignment {
    verticalAlignment_ = verticalAlignment;
    [self setNeedsDisplay];
}

- (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {
    CGRect textRect = [super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines];
    switch (self.verticalAlignment) {
        case VerticalAlignmentTop:
            textRect.origin.y = bounds.origin.y;
            break;
        case VerticalAlignmentBottom:
            textRect.origin.y = bounds.origin.y + bounds.size.height - textRect.size.height;
            break;
        case VerticalAlignmentMiddle:
            // Fall through.
        default:
            textRect.origin.y = bounds.origin.y + (bounds.size.height - textRect.size.height) / 2.0;
    }
    return textRect;
}

-(void)drawTextInRect:(CGRect)requestedRect {
    CGRect actualRect = [self textRectForBounds:requestedRect limitedToNumberOfLines:self.numberOfLines];
    [super drawTextInRect:actualRect];
}

封装了一个label类，使用方式和正常label一样

 myUILabel *laebl = [[myUILabel alloc] initWithFrame:CGRectMake(10, 100, 300, 200)];
    laebl.backgroundColor = [UIColor redColor];
    
    laebl.text = @"哈哈哈哈哈";
    //放到顶部
     [laebl setVerticalAlignment:VerticalAlignmentTop];
    //放到中间
  //  [laebl setVerticalAlignment:VerticalAlignmentMiddle];
    //放到最先面
   // [laebl setVerticalAlignment:VerticalAlignmentBottom];
    [self.view addSubview:laebl];

其他属性可以根据不同的属性去设置

代码下载：https://github.com/fenglingdeyi/myUILabel